1. Field of the Invention
The present invention relates to a supporting structure for a rotor, wherein the rotor shaft has a distal end face supported by a supporting portion of a supporting member, and wherein a permanent magnet and a balance plate attract each other such that the rotor shaft, except the distal end thereof, is not in frictional contact with the axle tube during rotation, thereby reducing the rotational noise and lengthening the longevity of the motor.
2. Description of the Related Art
FIG. 1 of the drawings illustrates a conventional motor structure that comprises a metal axle tube 90, a stator 91 mounted around the axle tube 90, a circuit board 92, and a balance plate 98. An oily bearing 93 is tightly engaged in the axle tube 90 for rotatably supporting a shaft 95 of a rotor 94. A distal end of the shaft 95 is rotatably supported by a support member 96. The rotor 94 rotates stably by means of mutual attraction between a permanent magnet 97 on the rotor 94 and the balance plate 98.
In such a conventional motor, the rotor 94 could not always rotate smoothly, as the lubricating oil in the oily bearing 93 leaks after the oily bearing 93 has been used for a period of time. In addition, the shaft 95 of the rotor 94 and the oily bearing 93 have a relatively large contact area therebetween. As a result, a relatively large friction exists and a larger noise is generated during rotation of the rotor 94. Furthermore, the cost for processing and manufacturing such a conventional motor is high.
It is the primary object of the present invention to provide a supporting structure for a rotor. The supporting structure can be manufactured conveniently. In addition, the shaft of the rotor and the supporting member for the shaft have a relatively smaller contact area therebetween.
It is another object of the present invention to provide a supporting structure for a rotor of a motor to thereby reduce the rotational noise and lengthen the longevity of the motor.
The present invention provides a combination of a rotor and a supporting structure for the rotor. The combination comprises an axle, a fixing member securely mounted in the axle tube, a supporting member securely mounted in the lower end of the axle tube, and a rotor having a shaft base and a shaft extending from the shaft base. The shaft includes an engaging groove. The shaft is extended through the fixing member with an end face of a distal end of the shaft rotatably resting on the supporting member and with the fixing member engaging with the engaging groove of the shaft. The shaft further includes an auxiliary supporting section, the auxiliary supporting section and an inner periphery of the axle tube having a minimal gap therebetween.